Update wkhtmltopdf version

[martinbertinat]

ISSUE TYPE

• Feature request

SUMMARY

Update wkhtmltopdf to last version with patched qt (adds some features). Current version is: 0.12.3.2

Goal

Some usefull features of wkhtmltopdf (like footer-html and header-html options) are only included in the "qt patched" version of wkhtmltopd. Goal version at least 0.12.4

To install the patched qt version inside the php container I followed these steps:

sudo apt-get purge wkhtmltopdf
wget https://github.com/wkhtmltopdf/wkhtmltopdf/releases/download/0.12.4/wkhtmltox-0.12.4_linux-generic-amd64.tar.xz
tar xvf wkhtmltox-0.12.4_linux-generic-amd64.tar.xz
sudo mv wkhtmltox/bin/wkhtmltopdf /usr/bin/wkhtmltopdf
sudo mv wkhtmltox/bin/wkhtmltoimage /usr/bin/wkhtmltoimage

[cytopia]

@martinbertinat PR is open and ready to be tested: #518